Nitroglycerin Vs Isoproterenol

[HopefulLady]

Ok I am wondering what the difference is between these 2 drugs Nitroglycerin VS Isoproterenol when used during a tilt table test. What sort of reactions or effects do they have on the nervous system? Do they produce the same reactions? And why would a doctor performing a TTT use one over the other?

[Birdlady]

I can't answer your questions because I've wondered this myself...

My local hospital did a TTT and used nitroglycerin which made my blood pressure dip into the high 90's and my heart rate nearly hit 180. Next month I plan on heading to Cleveland Clinic for more diagnostic testing and I was told that any TTT done with either nitro or Isopro are invalid and they must be redone. So...that is something to think about! I don't understand why one hospital/doctor use those drugs on everyone and then another hospital says they are completely useless...

Perhaps someone else can help clear this up for us both.

[mvdula]

I wish I knew the answer. They used iso on me - even tho I qualified for POTS before that injection. It just made my heart beat faster & more forcefully.....not fun.

[Poohbear]

See if this link helps you any...

http://www.hrsonline.org/Policy/DevicesDru...ble-Testing.cfm

[ramakentesh]

Nitroglycerin is a potent donor of nitric oxide which is the bodies main vasodilator - so it lowers blood pressure rapidly and dilates.

Isoproterenol off the top of my head acts on receptors (mainly beta) the same way as adrenaline - designed to increase sympathetic activity.

[Birdlady]

Nitroglycerin is a potent donor of nitric oxide which is the bodies main vasodilator - so it lowers blood pressure rapidly and dilates.

Isoproterenol off the top of my head acts on receptors (mainly beta) the same way as adrenaline - designed to increase sympathetic activity.

Thanks! I was hoping you'd poke in here ...So let me know if I am understanding this right. Basically from what I read in the link and from what you have said, they are trying to medically induce a syncope? I'm not exactly sure what that tells a physician if you do faint after the use of these drugs...What does it tell a physician if you don't faint?

[ramakentesh]

Other than in research studies its a pretty pointless exercise.

And it may make you feel pretty uncomfortable.

[Maxine]

I refused the Isoproterenol........now way was I going to let them give that to me, as I was already a mess. I was too weak for my heart to go into that kind of craziness. The Male RN that was working with the cardiologist resident was great about it. The test came out negative, but Dr. Grubb diagnosed POTs due to my history.

My BP fell 30 points, and heart rate went up 30 points, but it took longer because I was on my beta blockers. Now I have mornings that my heart goes crazy from rapid vasodialation-----probably like the nitro would do. I don't understand the purpose of adding the drugs if someone really has POTS they don't need it----I would think....

Maxine :0)

[HopefulLady]

I am having my tilt table done on Tuesday .. But my doctor only uses nitroglycerin in his office. I asked about the Isoprterenol because from what I have read that stuff works on adrenaline. I know I would def have a seriously bad reaction to that stuff. But I don't know about the Nitroglycerin because I wasn't sure if it stimulates that part of the nervous system that produces that adrenaline effect that my body does not react well to. Because I am on medication that does help prevent these adrenaline surges I am worried about the doctors not seeing my symptoms so to me the Isoproterenol based on what I have read would be the key to reproducing my symptoms during the test. However My doctors don't use the Iso in their office. I am wondering if the Nitro will have any effect on me I assumed it only affected those who have low BP which I don't. Mine is either normal or it's high.